Struct DeltaFn 

pub struct DeltaFn;

Tests whether two numbers are equal.

Returns 1 when values match and 0 otherwise.

Remarks

• If number2 is omitted, it defaults to 0.
• Inputs are numerically coerced.
• Uses a small numeric tolerance for floating-point comparison.

Examples

title: "Equal values"
formula: "=DELTA(5,5)"
expected: 1

title: "Default second argument"
formula: "=DELTA(2.5)"
expected: 0

related:
  - GESTEP
faq:
  - q: "Does `DELTA` require exact floating-point equality?"
    a: "It uses a small tolerance (`1e-12`), so values that differ only by tiny floating noise compare as equal."

Trait Implementations

impl Debug for DeltaFn

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Function for DeltaFn

[formualizer-docgen:schema:start] Name: DELTA Type: DeltaFn Min args: 1 Max args: variadic Variadic: true Signature: DELTA(arg1: number@scalar, arg2…: number@scalar) Arg schema: arg1{kinds=number,required=true,shape=scalar,by_ref=false,coercion=NumberLenientText,max=None,repeating=None,default=false}; arg2{kinds=number,required=true,shape=scalar,by_ref=false,coercion=NumberLenientText,max=None,repeating=None,default=false} Caps: PURE [formualizer-docgen:schema:end]

fn caps(&self) -> FnCaps

Capability flags for this function

fn name(&self) -> &'static str

fn min_args(&self) -> usize

fn variadic(&self) -> bool

fn arg_schema(&self) -> &'static [ArgSchema]

fn eval<'a, 'b, 'c>( &self, args: &'c [ArgumentHandle<'a, 'b>], _ctx: &dyn FunctionContext<'b>, ) -> Result<CalcValue<'b>, ExcelError>

The unified evaluation path.

fn namespace(&self) -> &'static str

fn volatile(&self) -> bool

fn aliases(&self) -> &'static [&'static str]

Optional list of additional alias names (case-insensitive) that should resolve to this function. Default: empty slice. Implementors can override to expose legacy names. Returned slice must have ’static lifetime (typically a static array reference).

fn function_salt(&self) -> u64

fn eval_reference<'a, 'b, 'c>( &self, _args: &'c [ArgumentHandle<'a, 'b>], _ctx: &dyn FunctionContext<'b>, ) -> Option<Result<ReferenceType, ExcelError>>

Optional reference result path. Only called by the interpreter/engine when the callsite expects a reference (e.g., range combinators, by-ref argument positions, or spill sources).

fn dispatch<'a, 'b, 'c>( &self, args: &'c [ArgumentHandle<'a, 'b>], ctx: &dyn FunctionContext<'b>, ) -> Result<CalcValue<'b>, ExcelError>

Dispatch to the unified evaluation path with automatic argument validation.